This is an application for a five-year competitive renewal for years 21-26 of the present NCI-Designated Mayo Comprehensive Cancer Center. Over the past four years, the Mayo Foundation has made a major investment in cancer research with construction of new laboratory space, recruitment of more than 25 basic scientists. and the creation of 9 basic science cores available to all investigators at the Institution. The expansion in basic science has led to the development of four new basic science programs in the Cancer Center: Cancer Genetics, Growth Factors, Cell Signalling, and Gene Regulation. These programs include the 25 investigators previously-participating in the former "Immunology" and "Biochemistry and Molecular Biology" programs as well as 30 new investigators. The programs in Clinical Trials and Cancer Pharmacology have also been strengthened by the addition of new personnel. In the current application, support is requested for nine cores: 1) Admini- stration, 2) Statistical and Clinical Research Support Systems, 3) Pharmacy, 4) Pathology, 5) Cellular Immunology , 6) Pharmacology, 7) Cytogenetics, 8) Molecular Probes, and 9) Peptide Synthesis and Sequencing. The Peptide Synthesis and Sequencing core is new. A capability for histologic preparation has been added to the Pathology Core (formerly "Tissue Distribution"). Increased developmental funds are requested to support a broadly based developing cancer control and prevention program, a developing program in radiation oncology, a state- of-the-art confocal microscopy/subcellular manipulation core, and an epidemiology core to support future programs in control and the new program in cancer genetics. Total direct costs requested in year 1 are $1.86 million.